Bugfix: Correctly handle given in Array params

Array parameters are handled as a parameter that opens a
scope with `type: Array`; `given` opens up a new scope, but
was always setting the type to Hash. This patch fixes that,
as well as correctly labeling the error messages associated
with array fields.

lib/grape/validations/params_scope.rb

@@ -42,37 +42,39 @@ def should_validate?(parameters)
  return false if @optional && (params(parameters).blank? ||
  any_element_blank?(parameters))
 
- @dependent_on.each do |dependency|
- if dependency.is_a?(Hash)
- dependency_key = dependency.keys[0]
- proc = dependency.values[0]
- return false unless proc.call(params(parameters).try(:[], dependency_key))
- elsif params(parameters).try(:[], dependency).blank?
- return false
+ if @dependent_on && !params(parameters).is_a?(Array)
+ @dependent_on.each do |dependency|
+ if dependency.is_a?(Hash)
+ dependency_key = dependency.keys[0]
+ proc = dependency.values[0]
+ return false unless proc.call(params(parameters).try(:[], dependency_key))
+ elsif params(parameters).try(:[], dependency).blank?
+ return false
+ end
  end
- end if @dependent_on
+ end
 
  return true if parent.nil?
  parent.should_validate?(parameters)
  end
 
  # @return [String] the proper attribute name, with nesting considered.
- def full_name(name)
+ def full_name(name, index: nil)
  if nested?
  # Find our containing element's name, and append ours.
- "#{@parent.full_name(@element)}#{array_index}[#{name}]"
+ [@parent.full_name(@element), [@index || index, name].map(&method(:brackets))].compact.join
  elsif lateral?
- # Find the name of the element as if it was at the
- # same nesting level as our parent.
- @parent.full_name(name)
+ # Find the name of the element as if it was at the same nesting level
+ # as our parent. We need to forward our index upward to achieve this.
+ @parent.full_name(name, index: @index)
  else
  # We must be the root scope, so no prefix needed.
  name.to_s
  end
  end
 
- def array_index
- "[#{@index}]" if @index.present?
+ def brackets(val)
+ "[#{val}]" if val
  end
 
  # @return [Boolean] whether or not this scope is the root-level scope
@@ -187,7 +189,7 @@ def new_lateral_scope(options, &block)
  element: nil,
  parent: self,
  options: @optional,
- type: Hash,
+ type: type == Array ? Array : Hash,
  dependent_on: options[:dependent_on],
  &block
  )

spec/grape/validations/params_scope_spec.rb

@@ -473,6 +473,29 @@ def initialize(value)
  end
  end
 
+ context 'when validations are dependent on a parameter within an array param' do
+ before do
+ subject.params do
+ requires :foos, type: Array do
+ optional :foo_type, :baz_type
+ given :foo_type do
+ requires :bar
+ end
+ end
+ end
+ subject.post('/test') { declared(params).to_json }
+ end
+
+ it 'applies the constraint within each value' do
+ post '/test',
+ { foos: [ { foo_type: 'a' }, { bar: 'not_needed', baz_type: 'c' } ] }.to_json,
+ { 'CONTENT_TYPE' => 'application/json' }
+
+ expect(last_response.status).to eq(400)
+ expect(last_response.body).to eq('foos[0][bar] is missing')
+ end
+ end
+
  context 'when validations are dependent on a parameter with specific value' do
  # build test cases from all combinations of declarations and options
  a_decls = %i(optional requires)